Omni-directional loudspeakers, which transmit sound in all directions are well-known. Typically, such loudspeakers have an axis along which at least one driver is mounted such that the driver's cone moves in an axial direction. Typically the axial direction is normal to the floor or ground of the area in which the loudspeaker is used. The driver generates sound waves which propagate either upwards away from or downwards towards the floor or ground. A sound reflector is positioned co-axially with the driver to reflect the sound waves to produce reflected waves which propagate away from the loudspeaker with equal strength in all directions. Such omni-directional speakers desirably provide a wide sound field which allows a person positioned in any direction around the loudspeaker to hear wide bandwidth sound produced by the loudspeaker.
Modern sound systems, including so-called home theatre systems, often incorporate 5 or more loudspeakers which are positioned at various locations within a listening room. The loudspeakers are preferably configured and positioned to provide a balanced sound field in a listening area. To increase the size of the listening area in which a relatively flat frequency response is achieved, it is desirable to use loudspeakers with a relatively wide sound field. To enhance the balance of the sound field at the listening position, it is desirable to control the shape of the sound field produced by any particular loudspeaker. To achieve a wide sound field from a loudspeaker, it is desirable to attain a wide dispersion pattern across a wide portion of the audible frequency range.
Accordingly, it is desirable to provide a loudspeaker that allows the wide sound field characteristics of an omni-directional loudspeaker to be shaped.